Some types of output devices include CRT monitors, LCD monitors and displays, gas plasma monitors and televisions. Ink jet printers, laser printers and sound cards are also types of output devices. An output device is any computer component that relays information to a user through text, graphics, audio or video. The information is known as a soft copy because it only exists electronically for a short period of time.
A CRT monitor contains a cathode ray tube, so it resembles a standard television set. The front of the glass cathode ray tube, also known as a CRT, features a screen that is coated with phosphor material that glows when an electron beam moves back and forth across it. This is what creates the images that are seen on the screen. The quality of the images that are displayed on a CRT monitor are determined by its resolution, dot pitch and refresh rate.
LCD monitors and displays both use liquid crystal to display information on the screen. A liquid crystal display, also known as an LCD, functions by passing an electric current through crystals, which are contained between two sheets of material. Images are created on the screen when light waves pass through some of the crystals, causing them to twist, which also blocks some of the light waves. The quality of the images that are seen on an LCD monitor or display are determined by its resolution.